Ribbon feeding mechanism



Jan. 5, 1954 E. M. LIPPERT RIBBON FEEDING MECHANISM 4 Sheets-Sheet 1 Filed Jan. 10. 1950 IN VEN TOR.

Zi/o/aerZ Erfzara f 4 Sheets-Sheet 2 Filed Jan. 10, 1950 v INVENTOR. Erfiana! M Lif /we r2 kfitorng a.

Jan. 5, 1954 E. M. LIPPERT RIBBON FEEDING MECHANISM 4 Sheets-Sheet 5 Filed Jan. 10, 1950 BY 3412s a? M Jan. 5, 1954 E. M. LIPPERT RIBBON FEEDING MECHANISM 4 Sheets-Sheet 4 Filed Jan. 10, 1950 A INVENTOR. Erfand ML/i a ner llllll Patented Jan. 5, 1954 RIBBON FEEDING MECHANISM Erhard M. Lippert, Chicago, 111., assignor to Victor Adding Machine (20., Chicago, 111., a corporation of Illinois Application January "10, 1950, Serial No. 137,784

v My invention relates generally to ribbon feeding and reversing mechanisms for calculating and similar machines, and more particularly to improved drive and detent devices for mechanisms of this character.

The ribbon feeding and reversing mechanism disclosed herein is of the type in which one of the ribbon spools is continuously driven through a frictional driving connection in one direction, and the other spool is driven by a reversible pawl mechanism which is capable of driving the latter spool in either direction, the reversal of the pawl being accomplished whenever the ribbon is completely unwound from thefirst spool, and the further drivin of the second spool is prevented by the tension of the ribbon when it is completely unwound from the first spool, it being understood that the ends of the ribbon are securely attachedrespectively to the spools.

In ribbon feeding and reversing mechanism of the above mentioned type, some difficulty has been experienced in the frictional drive mechanisms employed, sincethese become subject to wear in time, resulting in faulty operation of the mechanism. In accordance with the underlying principles of my invention, I employ an improved form of frictional drive mechanism, and in addition supply resilient detents which respectively hold the spools in the positions in which they are advanced by the driving mechanism.

A further object is to provide an improved ribbon feeding and reversing mechanism which is simple in construction, in which the-effects of wear over long periods of use are negligible, and which will therefore have a long useful life.

Other objects will appear from the following description, reference being had to the accompanying drawings, in which ;-Fig. 1- is a right side elevational view of an adding machine incorporating the invention, a portion of the casing being broken away to show the operating parts, and the main operating part being shown in section;

Fig. 2 isa left-side elevation of the rearward p'ortionof the adding machine, with a portion of the casing broken away to show the invention;

Fig.3 is a sectional view, taken on the line 3-3 of Fig} 1, showing the right-hand ribbon spool and itsdriving' mechanism;

Fig. 4-is an enlarged side sectional view, taken on the line 4--4 of Fig. 3; 1

5 Fig. 5 is' a sectional view of the right-hand ribbon spool, taken on the line 5-5 of Fig. 3;

Fi 6 is a sectional view of the left-hand rib- 1 Claim. (01. 242-70) 2 bon spool and its driving mechanism, taken on the line 66 of Fig. 2; 1

Figs. 7 and 8 are sectional views of the lefthand ribbon spools, taken on the lines 1-! and 8-8 of Fig. 6; and

Fig. 9 is a fragmentary enlarged sectional view of the right-hand ribbon spool, taken on the line 9--9 of Fig. 1. The invention is herein shown as forming part of a manually operated adding and listing ma chine, comprising a casing Ill having the usual numeral and operating keys. The operating handle is connected to the right-hand end of a main shaft 12 which has an operating cam plate I4 secured near its right-hand end, and a somewhat similar cam plate I6 (Fig. 2) secured near its left-hand end, these cam plates forming part of the driving connection between the mainshaft and the ribbon feeding and reversing mechanism.- =An inking ribbon l8 has its ends secured respectively to a right-hand spool 20 and a left-hand spool 22, and is suitably guided to extend across the face of a platen 24 which is suitably mounted in the frame of the machine, and is driven by a; suitable pawl and ratchet driving mechanism.

The right-hand ribbon spool 20' is mounted upon a sleeve 26 mounted for free rotation upon a stud 2B which is riveted to the right-hand frame plate 30 of the machine. The sleeve 26 is held on the stud 28 by a suitable keeper 32 and is staked to ment in one of a plurality of extruded cylindrical flanges 38 formed in the side wall of the right-' hand spool 29. As best shown in Fig. 4, the ratchet wheel 301s driven from the main shaft 12 through a link 40, the ends of which are respectively pivoted to thecam plate I4 and an oifsetarm 42- of a bell crank lever 44, the latter being staked-toahub 46 which is pivoted upon the enlargeddiameterportion 4'! of the stud 28, as best shown in Fig. 3.

The other arm 48 of the bell crank lever 44 has a small plate 50 riveted thereto by spacing studs 52 and 53, and has an elongated slot 54 formed therein in registry with a correspondingly shaped slot 56 formed in the arm 48. A double acting pawl 58 has sidewardly projecting ears 6!] which project through the slots 54 and 56 respectively, so as to be guided therein, the pawl 58 being held in engagement with the teeth of the ratchet wheel 34 'by a looped wire spring 62, one end of which is hooked about the spacing stud 52 and the other A detent lever 68 is pivoted upon a suitable fixed stud 68 and has a sidewardly bent rounded ear portion I8 engageable with the toothed periphery of the ratchet wheel 34, the'ear being held in this position by a suitably anchored tension spring I2. The restraining force applied to the ratchet wheel 34 by the detent 66 is suflicient to hold the ratchet wheel against movement as the pawl 58 slides over the teeth of the ratchet wheel 34 in the nondriving direction; but is not sufficient to cause the pawl 58 to change'its position to reverse its direction of drive.

It will be observed that the ribbon spool 28 is removably secured to the sleeve 26 by a notched lever I4 pivoted to the spool 28 by an extruded rivet I8 and having its notched portion engaging in a groove I8 formed near the outer end of the sleeve 26, the lever I4 being held in such position by a suitable embossing 88 (Fig. 1) which engages in a suitable hole in the side of the. spool 28, it being understood that the lever I4 is sufficiently resilient to cause engagement of the embossed part 88 with such hole in the spool wall.

The left-hand spool 22', which isbest shown in Figs. 6 and 7, is mounted upon a sleeve 82 which is freely rotatable upon astud 84 riveted to the-left frame plate 86 of the machine. The sleeve 82 is counterbored to provide a recess for a compression coil spring 88, one'end of which presses against the shoulder at the end' of the counterbore, and the other end of which bears against a friction disc 88 which is'freely rotatable upon the stud 84.

The disc 98 is provided-With suitable openings 92 for the reception of the extruded cylindrical flange 38 of the ribbon spool 22 (which is of the same construction as the-spool 28). The keeper 32 for holding the sleeve 82 on the stud 84, and the locking lever I4 for holding the spool 22 on the sleeve 82, are similar'to the correspondingly numbered parts previously described; and operate in the same manner.

A ratchet wheel 94 is freely mounted for rotation on the enlarged portion 980i stud 84, and has a second friction plate 98 keyed thereto by virtue of the fact that the plate 88 has notches 99 registrable with the recessed portions of teeth I88, asbest shown in Fig. 7. Interposed between the friction plates 98 and'98, isan annular'fric tion-disc I82 madeof a suitable-friction-gasketlike'material. It will be noted that the friction disc I82 is of relatively large'diameter sorthatit' will be capable of transmittinga large torque over long periods of time, without substantial wear. thus making it necessary that thespring 88 need apply but a very small forcein-holding the'friction plate 98 against the friction'disc I02.

A dentent pawl I 84 is suitably pivoted on a stud I85 secured to the left-hand frame plate, and has a plurality of closely spaced teeth I88, any one of which may engage with one of the teeth I 88 of the ratchet wheel 94 so as'to prevent retrograde movement thereof from the maximum position to which it may be moved. The pawl 4 I84 is held in operative position by a suitable anchored tension spring I89.

The ratchet wheel 94 is also engaged by an actuating pawl II8 pivotally secured to the cam plate I6 by a stud H2 and having a plurality of teeth 4 engageable with the teeth I88 of the ratchet wheel 84, the teeth II4 being resiliently maintained in contact with .theteeth of the ratchet wheel 94 by a suitably anchored tension spring IIG. As a safety measure, a bushing H8 is secured to the frame plate 86 in position so that if the spring IIG should break or become disconnected, the pawl IIIl may slide back and forth freely without causing breakage due to jamming with other parts of the mechanism.

The ends of the ribbon I8 are fixed respectively to the spools 28 and 22, and the ribbon is guided so as to pass below the platen 24 by suitably formed guides I28 (Fig. 7) and I22 (Fig. 4), each of these guides being provided with a suitably curled clip I24 to provide a smooth guiding surface for'the ribbon. The ribbon also passes around an idler roller I26 suitably mount ed for rotation on anarm- I28 pivoted on-a stud I38 carried by a downwardly projecting part of the right-hand guide I22, and having its pivotal movement limited by a shouldered screw I32 projecting through an elongated slot I34 formedin the arm I28, the screw I32 being threaded in the right-hand sideplate 38, and serving as part of the means to attach the bracket I22 to the frame plate 38. The army I28 is'blasedto SW clockwise (Fig. 4) by a suitably anchored tension spring I36. The'purpose of the roller I26 is to take up any slack in the ribbon which may occurduring certain conditions of operation.v

In operation, the bell crank (Fig 4) and the pawl III) operate upon each reciprocation of the main shaft I2 to drive their respective ratchet wheels 34 and 94. it being understood,.,however, that the drive by the pawl .I I 8 is. effected through the friction drive provided'by the plates 98 and 88 and the friction disc I82; The force applied to the pawl 58 by the spring 62 is sumcient to overcome the friction in the mechanism as well as the friction capable of being transmitted through the friction drive provided by the plates 98 and 98 and friction disc I82.

Thus, assuming that the ribbon has been Wound upon the left-hand spool 22 andthe ratchet wheel 34 is being driven counterclockwise (Fig. 4), upon the return stroke of the operating handle, that is, upon clockwiserotation (Fig. l) of the main shaft I2, the ratchet wheel 34 will cause'the ribbon to be wound up upon the right-hand spool 28, since the driving mechanism for the right-hand spool applies sufficient driving torque to'this spool to overcome the'friction applied by the friction-drive 98-, 98, I82, as well as to overcome other frictional forcestending'to retard movement of the ribbon. Under theseconditions, the'ribbon will'be unwoundfromthe left-hand spooland wound uponthe right-hand spool, until it has been completely unwound from the lefthand spool. Thereafterfurtherrotation of the ratchet wheel .34 will be'prevented by the restraining tension of the ribbon itself. Upon the counterclockwise swinging movement of the bell crank 44, the pawl 58 will be forced upwardly in the slots 54 against-the force applied by the spring 82, and will be moved from the position in which it is shown in full lines in Fig. 4 to the position inv which it is shown in dotted lines.

Following this reversal of the pawl 58, the

the left-hand spool 22, the pawl 53 continues to drive the ratchet wheel 34, and hence the righthand spool 20, in a clockwise direction, rewinding the ribbon upon the right-hand spool 29 in a direction opposite to that in which it was previously wound.

After the ribbon has been completely unwound from the left-hand spool 22 and wound upon the right-hand spool 20, the retarding force applied through the tension of the ribbon again holds the ratchet wheel 34 from clockwise rotation by the pawl 53, and the latter is thus forced to return to its full line position. Thereafter it drives the ratchet wheel 36 and right-hand spool 20 counterclockwise, unwinding the ribbon from the spool 20 and permitting it to be rewound upon the spool 22, at a rate determined by the action of the pawl 58 upon the ratchet wheel 34.

During the return operating stroke, it will thus appear, a short length of ribbon is unwound from the right-hand spool 20, and under these conditions the slack takeup roller !26 swings clockwise (Fig. 4) so as to take up this slack. Upon the next following forward operating stroke, the pawl H0, through its drive with the ratch t wheel 90, rotates the left-hand spool 22 counterclockwise (Fig. 7), and this slack in the ribbon is again taken up and the ribbon wound upon the spool 22, since the stroke of the pawl H0 is more than sufficient to take up the length of the ribbon which is unwound by the ratchet wheel 34, the surplusage of movement of the ratchet wheel 94 being dissipated in relative movement of plates 90 and 90 due to their slippage relative to the friction disc I02.

After the ribbon has been completely unwound from the righthand spool 20, the pawl 58 continues to drive the right-hand spool 20 in a counterclockwise direction, again winding the ribbon upon the right-hand spool 20 in a manner previously described.

The unwinding from the right-hand spool 20 cannot exceed the rate at which the spool 20 is driven by the pawl 58, because of the restraining force applied by the detent 0%. Furthermore, the detent 66 operates to prevent retrograde movement of the ratchet wheel 35 under the influence of the resiliency within the length of the ribbon extending between the two spools, which would otherwise prevent the pawl 58 from advancing past one of the teeth of the ratchet wheel 3 and thus would make it improbable that the pawl 53 would have its position reversed in the manner above described.

While I have shown and described a preferred embodiment of my invention, it will be apparent that numerous variations and modifications thereof may be made without departing from the underlying principles of the invention. I therefore desire, by the following claim, to include within the scope of the invention all such variations and modifications by which substantially the results of my invention may be obtained through the use of substantially the same or equivalent means.

I claim:

In a ribbon feeding mechanism, the combination of a stud, a driving wheel including a first friction plate mounted for rotation on the stud, a sleeve rotatable on the stud, said sleeve having an internal counterbore, a second friction plate mounted for rotation on the stud between the sleeve and the first friction plate, a friction disc between the plates, a coil spring located in the counterbore and compressed between the sleeve and the second friction plate to urge the plates into frictional driving relation, a ribbon spool detachably secured to the sleeve and having means forming a positive rotary driving con-- nection with the second friction plate, and means forming shoulders on the opposite ends of the stud to retain the sleeve and the plates on the stud and to transmit the end thrust of the spring to the opposite ends of the stud.

ERI'IARD I 5. LIPPERT.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 101,940 Tatham Apr. 12, 1870 345,347 W'haley July 13, 1836 396,070 Burroughs Jan. 15, 1889 534,072 Morris Feb. 12, 1895 712,538 Howell Nov. 4, 1002 1,030,097 Ledeboer a- June 18, 1912 1,083,580 Zenke 6, 1914; 1,199,512 Verges Sept. 26, 1916 

